Real-time implementation of 3D LiDAR point cloud semantic segmentation in an FPGA

Dissertação de mestrado em Informatics EngineeringIn the last few years, the automotive industry has relied heavily on deep learning applications for perception solutions. With data-heavy sensors, such as LiDAR, becoming a standard, the task of developing low-power and real-time applications has become increasingly more challenging. To obtain the maximum computational efficiency, no longer can one focus solely on the software aspect of such applications, while disregarding the underlying hardware. In this thesis, a hardware-software co-design approach is used to implement an inference application leveraging the SqueezeSegV3, a LiDAR-based convolutional neural network, on the Versal ACAP VCK190 FPGA. Automotive requirements carefully drive the development of the proposed solution, with real-time performance and low power consumption being the target metrics. A first experiment validates the suitability of Xilinx’s Vitis-AI tool for the deployment of deep convolutional neural networks on FPGAs. Both the ResNet-18 and SqueezeNet neural networks are deployed to the Zynq UltraScale+ MPSoC ZCU104 and Versal ACAP VCK190 FPGAs. The results show that both networks achieve far more than the real-time requirements while consuming low power. Compared to an NVIDIA RTX 3090 GPU, the performance per watt during both network’s inference is 12x and 47.8x higher and 15.1x and 26.6x higher respectively for the Zynq UltraScale+ MPSoC ZCU104 and the Versal ACAP VCK190 FPGA. These results are obtained with no drop in accuracy in the quantization step. A second experiment builds upon the results of the first by deploying a real-time application containing the SqueezeSegV3 model using the Semantic-KITTI dataset. A framerate of 11 Hz is achieved with a peak power consumption of 78 Watts. The quantization step results in a minimal accuracy and IoU degradation of 0.7 and 1.5 points respectively. A smaller version of the same model is also deployed achieving a framerate of 19 Hz and a peak power consumption of 76 Watts. The application performs semantic segmentation over all the point cloud with a field of view of 360°.Nos últimos anos a indústria automóvel tem cada vez mais aplicado deep learning para solucionar problemas de perceção. Dado que os sensores que produzem grandes quantidades de dados, como o LiDAR, se têm tornado standard, a tarefa de desenvolver aplicações de baixo consumo energético e com capacidades de reagir em tempo real tem-se tornado cada vez mais desafiante. Para obter a máxima eficiência computacional, deixou de ser possível focar-se apenas no software aquando do desenvolvimento de uma aplicação deixando de lado o hardware subjacente. Nesta tese, uma abordagem de desenvolvimento simultâneo de hardware e software é usada para implementar uma aplicação de inferência usando o SqueezeSegV3, uma rede neuronal convolucional profunda, na FPGA Versal ACAP VCK190. São os requisitos automotive que guiam o desenvolvimento da solução proposta, sendo a performance em tempo real e o baixo consumo energético, as métricas alvo principais. Uma primeira experiência valida a aptidão da ferramenta Vitis-AI para a implantação de redes neuronais convolucionais profundas em FPGAs. As redes ResNet-18 e SqueezeNet são ambas implantadas nas FPGAs Zynq UltraScale+ MPSoC ZCU104 e Versal ACAP VCK190. Os resultados mostram que ambas as redes ultrapassam os requisitos de tempo real consumindo pouca energia. Comparado com a GPU NVIDIA RTX 3090, a performance por Watt durante a inferência de ambas as redes é superior em 12x e 47.8x e 15.1x e 26.6x respetivamente na Zynq UltraScale+ MPSoC ZCU104 e na Versal ACAP VCK190. Estes resultados foram obtidos sem qualquer perda de accuracy na etapa de quantização. Uma segunda experiência é feita no seguimento dos resultados da primeira, implantando uma aplicação de inferência em tempo real contendo o modelo SqueezeSegV3 e usando o conjunto de dados Semantic-KITTI. Um framerate de 11 Hz é atingido com um pico de consumo energético de 78 Watts. O processo de quantização resulta numa perda mínima de accuracy e IoU com valores de 0.7 e 1.5 pontos respetivamente. Uma versão mais pequena do mesmo modelo é também implantada, atingindo uma framerate de 19 Hz e um pico de consumo energético de 76 Watts. A aplicação desenvolvida executa segmentação semântica sobre a totalidade das nuvens de pontos LiDAR, com um campo de visão de 360°

A High-Performance System Architecture for Medical Imaging

Medical imaging is classified into different modalities such as ultrasound, X-ray, computed tomography (CT), positron emission tomography (PET), magnetic resonance imaging (MRI), single-photon emission tomography (SPECT), nuclear medicine (NM), mammography, and fluoroscopy. Medical imaging includes various imaging diagnostic and treatment techniques and methods to model the human body, and therefore, performs an essential role to improve the health care of the community. Medical imaging, scans (such as X-Ray, CT, etc.) are essential in a variety of medical health-care environments. With the enhanced health-care management and increase in availability of medical imaging equipment, the number of global imaging-based systems is growing. Effective, safe, and high-quality imaging is essential for the medical decision-making. In this chapter, we proposed a medical imaging-based high-performance hardware architecture and software programming toolkit called high-performance medical imaging system (HPMIS). The HPMIS can perform medical image registration, storage, and processing in hardware with the support of C/C++ function calls. The system is easy to program and gives high performance to different medical imaging applications

CNNParted: An open source framework for efficient Convolutional Neural Network inference partitioning in embedded systems

Applications such as autonomous driving or assistive robotics heavily rely on the usage of Deep Neural Networks. In particular, Convolutional Neural Networks (CNNs) provide precise and reliable results in image processing tasks like camera-based object detection or semantic segmentation. However, to achieve even better results, CNNs are becoming more and more complex. Deploying these networks in distributed embedded systems thereby imposes new challenges, due to additional constraints regarding performance and energy consumption in the near-sensor compute platforms, i.e. the sensor nodes. Processing all data in the central node, however, is disadvantageous since raw data of camera consumes large bandwidth and running CNN inference of multiple tasks requires certain performance. Moreover, sending raw data over the interconnect is not advisable for privacy reasons. Hence, offloading CNN workload to the sensor nodes in the system can lead to reduced traffic on the link and a higher level of data security. However, due to the limited hardware-resources on the sensor nodes, partitioning CNNs has to be done carefully to meet overall latency requirements and energy constraints. Therefore, we present CNNParted, an open-source framework for efficient, hardware-aware CNN inference partitioning targeting embedded AI applications. It automatically searches for potential partitioning points in the CNN to find a beneficial workload distribution between sensor nodes and a central edge node. Thereby, CNNParted not only analyzes the CNN architecture but also takes hardware components, such as dedicated hardware accelerators and memories, into consideration to evaluate inference partitioning regarding latency and energy consumption. Exemplary, we apply CNNParted to three commonly used feed forward CNNs in embedded systems. Thereby, the framework first searches for several potential partitioning points and then evaluates the latter regarding inference latency and energy consumption. Based on the results, beneficial partitioning points can be identified depending on the system constraints. Using the framework, we are able to find and evaluate 10 potential partitioning points for FCN ResNet-50, 13 partitioning points for GoogLeNet, and 8 partitioning points for SqueezeNet V1.1 within 520 s, 330 s, and 140 s, respectively, on an AMD EPYC 7702P running 8 concurrent threads. For GoogLeNet, we determine two partitioning points that provide a good trade-off between required bandwidth, latency and energy consumption. We also provide insights into further interesting findings that can be derived from the evaluation results

Adaptively Lossy Image Compression for Onboard Processing

More efficient image-compression codecs are an emerging requirement for spacecraft because increasingly complex, onboard image sensors can rapidly saturate downlink bandwidth of communication transceivers. While these codecs reduce transmitted data volume, many are compute-intensive and require rapid processing to sustain sensor data rates. Emerging next-generation small satellite (SmallSat) computers provide compelling computational capability to enable more onboard processing and compression than previously considered. For this research, we apply two compression algorithms for deployment on modern flight hardware: (1) end-to-end, neural-network-based, image compression (CNN-JPEG); and (2) adaptive image compression through feature-point detection (FPD-JPEG). These algorithms rely on intelligent data-processing pipelines that adapt to sensor data to compress it more effectively, ensuring efficient use of limited downlink bandwidths. The first algorithm, CNN-JPEG, employs a hybrid approach adapted from literature combining convolutional neural networks (CNNs) and JPEG; however, we modify and tune the training scheme for satellite imagery to account for observed training instabilities. This hybrid CNN-JPEG approach shows 23.5% better average peak signal-to-noise ratio (PSNR) and 33.5% better average structural similarity index (SSIM) versus standard JPEG on a dataset collected on the Space Test Program – Houston 5 (STP-H5-CSP) mission onboard the International Space Station (ISS). For our second algorithm, we developed a novel adaptive image-compression pipeline based upon JPEG that leverages the Oriented FAST and Rotated BRIEF (ORB) feature-point detection algorithm to adaptively tune the compression ratio to allow for a tradeoff between PSNR/SSIM and combined file size over a batch of STP-H5-CSP images. We achieve a less than 1% drop in average PSNR and SSIM while reducing the combined file size by 29.6% compared to JPEG using a static quality factor (QF) of 90